The subject matter disclosed herein relates to inflation systems and, more particularly, to inflation systems with fast acting pressure balanced, pilot-type solenoid valves.
Pneumatic inflation systems often use stored high pressure gas sources to inflate an inflatable element. The stored high pressure gas sources are normally designed to be discharged within a specified time by the opening of an inflation valve that is normally-closed. Some pneumatic inflation systems, such as those employed in helicopter life rafts and floats, make use of inflation valves that are actuated by electrical initiators with explosive materials. Such electrical initiators are commonly referred to as “electrical squibs” and each one typically includes a valve housing with a linear sliding-type valve element and an actuation housing with a piston seal assembly. An inlet of the inflation valve is connected to a gas bottle and the fluid pressure force is effective at the valve element. Energization of the electrical squib initiator causes an actuator piston to move in the actuator housing which in turn initiates an opening movement of the valve element to discharge the high pressure gas from the stored gas bottle to the downstream inflatable.
Being elements of survival systems, inflation valves such as those described above do not tend to include or require any return forcing elements. That is, in the initial closed position, the valve elements of the inflation valves are retained by actuator piston rod assembled inside the actuation housing, for example, but once the valve is opened by the initiator the opening position is sustained by the fluid inlet pressure force acting on the valve poppet. This leads to electrical squib initiators having certain disadvantages, such as being single shot devices and having main valve maintainability issues and safety compliance issues.